The standard wheelbarrow has a wheel at the forward end to carry the load and a pair of generally parallel handles that project rearwardly to be grasped by the hands of the person using the wheelbarrow. A very difficult problem arises when it is necessary to empty a very heavy load, such as wet concrete, in a desired location. The operator when lifting the handles has to maintain a tight grip on them to prevent the load from spilling sidewise. At the same time it becomes increasingly difficult to manipulate the handles when they start to assume a more nearly vertical position, which they must do in order to empty the load.
Not only is it very difficult to empty such a heavy load from the wheelbarrow, but the person doing it may have to change the position of their hands on the wheelbarrow handle, or alternatively must twist his or her hands through as much as 180 degrees of rotation in order to empty the load. In that twisting action the person may suffer the serious injury that is known as repetitive-motion or carpel tunnel syndrome injury. Or if the person's hands are removed and then engaged in a different position on the handle of the wheelbarrow, there is a risk of spilling the load in the wrong location.